<template>
  <div class="app-container">
    <h2 style="text-align: center;">课程目录</h2>
    <!--查询表单-->
    <el-form :inline="true"
             class="demo-form-inline">
      <!-- 所属分类：级联下拉列表 -->
      <!-- 一级分类 -->
      <el-form-item label="课程类别">
        <el-select v-model="searchObj.subjectParentId"
                   placeholder="请选择"
                   @change="subjectLevelOneChanged">
          <el-option v-for="subject in subjectNestedList"
                     :key="subject.id"
                     :label="subject.title"
                     :value="subject.id" />
        </el-select>
        <!-- 二级分类 -->
        <el-select v-model="searchObj.subjectId"
                   placeholder="请选择">
          <el-option v-for="subject in subSubjectList"
                     :key="subject.id"
                     :label="subject.title"
                     :value="subject.id" />
        </el-select>
      </el-form-item>
      <!-- 标题 -->
      <el-form-item>
        <el-input v-model="searchObj.courseTitle"
                  placeholder="课程标题" />
      </el-form-item>
      <!-- 讲师 -->
      <el-form-item>
        <!-- <el-select v-model="searchObj.teacherId"
                   placeholder="请选择讲师">
          <el-option v-for="teacher in teacherList"
                     :key="teacher.id"
                     :label="teacher.name"
                     :value="teacher.id" />
        </el-select> -->
        <el-input v-model="searchObj.teacherName"
                  placeholder="课程讲师" />
      </el-form-item>
      <el-button type="primary"
                 icon="el-icon-search"
                 @click="fetchData()">查询</el-button>
      <el-button type="default"
                 @click="resetData()">清空</el-button>
    </el-form>

    <!-- 表格 -->
    <el-table v-loading="listLoading"
              :data="list"
              element-loading-text="数据加载中"
              border
              fit
              highlight-current-row
              row-class-name="myClassList">
      <el-table-column label="序号"
                       width="70"
                       align="center">
        <template slot-scope="scope">
          {{ (page - 1) * limit + scope.$index + 1 }}
        </template>
      </el-table-column>
      <el-table-column label="课程信息"
                       width="470"
                       align="center">
        <template slot-scope="scope">
          <div class="info">
            <div class="pic">
              <img :src="scope.row.cover"
                   alt="scope.row.title">
            </div>
            <div class="title">
              <a href="">{{ scope.row.title }}</a>
              <p>{{ scope.row.lessonNum }}课时</p>
            </div>
          </div>
        </template>
      </el-table-column>
      <el-table-column label="创建时间"
                       align="center">
        <template slot-scope="scope">
          {{ scope.row.gmtCreate.substr(0, 10) }}
        </template>
      </el-table-column>
      <el-table-column label="发布状态"
                       align="center">
        <template slot-scope="scope">
          {{ scope.row.status==='Draft'?'未发布':'已发布' }}
        </template>
      </el-table-column>
      <el-table-column label="价格"
                       width="100"
                       align="center">
        <template slot-scope="scope">
          {{ Number(scope.row.price) === 0 ? '免费' :
            '¥' + scope.row.price.toFixed(2) }}
        </template>
      </el-table-column>
      <el-table-column prop="buyCount"
                       label="付费学员"
                       width="100"
                       align="center">
        <template slot-scope="scope">
          {{ scope.row.buyCount }}人
        </template>
      </el-table-column>
      <el-table-column label="操作"
                       width="150"
                       align="center">
        <template slot-scope="scope">
          <router-link :to="'/edu/course/info/'+scope.row.id">
            <el-button type="text"
                       size="mini"
                       icon="el-icon-edit">编辑课程信息</el-button>
          </router-link>
          <router-link :to="'/edu/course/chapter/'+scope.row.id">
            <el-button type="text"
                       size="mini"
                       icon="el-icon-edit">编辑课程大纲</el-button>
          </router-link>
          <el-button type="text"
                     size="mini"
                     icon="el-icon-delete"
                     @click="removeDataById(scope.row.id)">删除</el-button>
        </template>
      </el-table-column>
    </el-table>
    <!-- 分页 -->
    <el-pagination :current-page="page"
                   :page-size="limit"
                   :total="total"
                   style="padding: 30px 0; text-align: center;"
                   layout="total, prev, pager, next, jumper"
                   @current-change="fetchData" />
  </div>
</template>

<script>
import course from '@/api/edu/course'
import teacher from '@/api/edu/teacher'
import subject from '@/api/edu/subject'

export default {
  data() {
    return {
      listLoading: true, // 是否显示loading信息
      list: null, // 数据列表
      total: 0, // 总记录数
      page: 1, // 页码
      limit: 10, // 每页记录数
      searchObj: {
        subjectParentId: '',
        subjectId: '',
        courseTitle: '',
        teacherName: ''
      }, // 查询条件
      teacherList: [], // 讲师列表
      subjectNestedList: [], // 一级分类列表
      subSubjectList: [] // 二级分类列表,
    }
  },
  created() {
    // 当页面加载时获取数据
    this.fetchData()
    // 初始化分类列表
    this.initSubjectList()
    // 获取讲师列表
    this.initTeacherList()
  },
  methods: {
    fetchData(page = 1) {
      // 调用api层获取数据库中的数据
      // 当点击分页组件的切换按钮的时候，会传输一个当前页码的参数page
      // 解决分页无效问题
      this.page = page
      this.listLoading = true
      course.getPageList(this.page, this.limit, this.searchObj).then(response => {
        if (response.success === true) {
          this.list = response.data.rows
          this.total = response.data.total
        }
        this.listLoading = false
      })
    },
    initTeacherList() {
      teacher.getList().then(response => {
        this.teacherList = response.data.items
      })
    },
    initSubjectList() {
      subject.getNestedTreeList().then(response => {
        this.subjectNestedList = response.data.list
      })
    },
    subjectLevelOneChanged(value) {
      for (let i = 0; i < this.subjectNestedList.length; i++) {
        if (this.subjectNestedList[i].id === value) {
          this.subSubjectList = this.subjectNestedList[i].children
          this.searchObj.subjectId = ''
        }
      }
    },
    resetData() {
      this.searchObj = {}
      this.subSubjectList = [] // 二级分类列表
      this.fetchData()
    },

    // 根据id值删除
    removeDataById(id) {
      this.$confirm('此操作将永久删除该课程，以及该课程下的章节和视频，是否继续?', '提示', {
        confirmButtonText: '确定',
        cancelButtonText: '取消',
        type: 'warning'
      }).then(() => {
        return course.removeById(id)
      }).then(() => {
        this.fetchData()
        this.$message({
          type: 'success',
          message: '删除成功!'
        })
      }).catch((response) => { // 失败
        if (response === 'cancel') {
          this.$message({
            type: 'info',
            message: '已取消删除'
          })
        }
      })
    }
  }
}
</script>

<style scoped>
.myClassList .info {
  width: 450px;
  overflow: hidden;
}
.myClassList .info .pic {
  width: 150px;
  height: 90px;
  overflow: hidden;
  float: left;
}
.myClassList .info .pic a {
  display: block;
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 0;
}
.myClassList .info .pic img {
  display: block;
  width: 100%;
  height: 100%;
}
.myClassList td .info .title {
  width: 280px;
  float: right;
  height: 90px;
}
.myClassList td .info .title a {
  display: block;
  height: 48px;
  line-height: 24px;
  overflow: hidden;
  color: #00baf2;
  margin-bottom: 12px;
}
.myClassList td .info .title p {
  line-height: 20px;
  margin-top: 5px;
  color: #818181;
}
</style>
